Xizhou Teachers University

In this paper, in search of an approach for tuning the single-mol. magnet behaviors in lanthanide polynuclear compounds, two new dinuclear dysprosium compounds based on an 8-hydroxyquinoline Schiff base and two different β-diketonate ligands, [Dy₂(hfac)₄L₂] (1) and [Dy₂(tfac)₄L₂] (2) (HL = 2-[[(4-iodophenyl)imino]methyl]-8-hydroxyquinoline, hfac = hexafluoroacetylacetonate and tfac = trifluoroacetylacetonate), have been synthesized, structurally and magnetically characterized. The two Dy₂ compounds have very similar structures, however, magnetic studies reveal that 1 and 2 showed different SMM behaviors with energy barriers of 15.70 K for 1 and 6.57 K for 2. The different SMM behaviors mainly result from the different coordination environments of the central Dy^III ions in 1 and 2.

Amaranthus waxy starch was blended and kneaded with D-fructose, egg albumin and/or Et stearate to form semiartificial complexes. These complexes were then thermolyzed at 20-300° in a crucible of derivatograph. Thermoanal. studies of thermal gravimetry, differential thermogravimetry and differential thermoanal. revealed that any generation of free radicals was manifested by no well-defined energetic effect and proceeded after the main thermal effects due to the decomposition of starch. It corresponded to the end of a rapid decomposition, i.e. to the 59-66% sample weight loss.

Nine starch varieties were blended and kneaded with D-fructose, D-glucose, sucrose, egg albumin and/or Et stearate to form semiartificial complexes. They were then thermolyzed and the numbers of unpaired spins in the solid residues were determined Individual starch varieties began to generate unpaired spin states within 2 h of heating at 285° but some starch blends, particularly those of 4-component starch (10:1:1:1) mixtures, generated free radicals within 2 h of heating at 160°. The free radical counts were minimized by the mutual complexation of the blend components and, to a certain extent, by the free radical scavenging in the blends.